Mercury speciation in Pacific coastal rainwater,Monterey Bay,California

We measured mercury speciation in coastal rainwater samples from Monterey Bay, California in 2007–2008 to investigate the source of monomethylmercury (MMHg) in rainwater and determine the relative importance of wet atmospheric deposition of MMHg to coastal waters compared to other sources on the central Pacific coast. Total mercury (HgT) ranged from 10 to 88 pM, with a sample mean ± standard deviation of 33 ± 22 pM (volume-weighted average 29 pM). MMHg concentrations ranged from 0.12 to 2.3 pM with a sample mean of 0.7 ± 0.5 pM (volume-weighted average 0.68 pM). Reactive mercury (HgR) concentrations ranged from 0.87 to 47 pM, sample mean 7.8 ± 8.3 pM (volume-weighted average 6.1 pM). Acetate concentration in rainwater, measured in a subset of samples, ranged from 0.34 to 3.1 μM, and averaged 1.6 ± 0.9 μM (volume-weighted average 1.3 μM). Dimethylmercury (DMHg) concentrations were below the limit of detection in air (<0.01 ng m^?3) and rainwater (<0.05 pM). Despite previous suggestions that DMHg in upwelled ocean waters is a potential source of MMHg in coastal rainwater, MMHg in rain was not related to coastal upwelling seasons or surface water DMHg concentrations. Instead, a multiple linear regression analysis demonstrated that MMHg concentrations were positively and significantly correlated (p = 0.002, adjusted R² = 0.88) with those of acetate and HgR. These data appear to support previous suggestions that the aqueous phase methylation of Hg(II) by acetate may be the source of MMHg in rainwater, but imply that acetate concentrations in rainwater play a more important role relative to HgR than previously hypothesized. However, the calculated chemical speciation of Hg(II) in rainwater and the minimal predicted complexation of Hg(II) by acetate suggest that the aqueous phase methylation of Hg(II) by acetate is unlikely to account for the MMHg found in precipitation, or that the mechanism of this reaction in the atmosphere differs from that previously reported (Gardfeldt et al., 2003).     

Risk estimation and annual fluxes of emerging contaminants from a Scottish priority catchment to the estuary and North Sea

Environmental Geochemistry and Health - Emerging contaminants (ECs) such as endocrine-disrupting chemicals (EDCs) and pharmaceuticals and personal care products (PPCPs) attracted global concern...     

Integument and defence in larva and prepupa of a sawfly living on a semi-aquatic plant

The larvae of the sawfly Rhadinoceraea micans live and feed on a semi-aquatic plant, Iris pseudacorus, and their integument is strongly hydrophobic. The hydrophobicity is part of a chemical defence strategy, easy bleeding, also known from congeners. The prepupae burrow into the soil where they form a cocoon in which they pupate, thus implying different micro-environmental conditions. The cuticle structure and wetting defensive effectiveness of R. micans were compared between larvae and prepupae. The two stages were similarly well defended against attacking ants by the bleeding of a deterrent hemolymph, whereas they were dissimilar in the cuticle surface that presented sculptures and wax crystals at the larval stage only. The integument of prepupae was less structured, and hydrophilic. Larvae of R. micans exhibit, among sawflies, an exceptional cuticle structuring and we assume that they occupy this particular niche of a semi-aquatic environment to avoid encounters with ground-dwelling predators whereas prepupae may benefit from the chemical defence acquired at larval stage.     

Advancing objectives-based,integrated ocean management through marine spatial planning: current and future directions on the Scotian Shelf off Nova Scotia,Canada

The national legislative and policy context for integrated ocean management in Canada is provided by the Oceans Act (1996) and the supporting policy statement, Canada’s Oceans Strategy. Under the Oceans Act, Fisheries and Oceans Canada (DFO) is the lead federal authority for ocean affairs and is charged with leading and facilitating the development and implementation of integrated management plans for all marine waters. Integrated management efforts in Canada are being undertaken through an area-based approach that enables marine planning, management and decision making to occur at appropriate spatial scales, from regional to site-specific. This article focuses on the Eastern Scotian Shelf Integrated Management (ESSIM) process, an offshore-focused effort to develop an integrated ocean management plan for a large portion of the Scotian Shelf, off Nova Scotia. The resulting Eastern Scotian Shelf Integrated Ocean Management Plan (the ESSIM plan) has been developed through a collaborative process involving all interested and affected government departments and ocean stakeholders, and provides an objectives-based approach to ocean management. The ESSIM plan contains a set of long-term, overarching goals for collaborative governance and integrated management, sustainable human use, and healthy ecosystems. These goals are supported by more specific objectives that express desired outcomes and conditions for the marine region. The objectives-based approach seeks to ensure that interrelationships among ecosystem and human use objectives are recognized and reflected in the identification of management strategies and supporting actions. This article considers the role of marine spatial planning within the context of the integrated ocean management process underway for the Scotian Shelf. The policy and management context for integrated ocean management in Canada is briefly described and a summary of the ESSIM plan is provided. The current and potential role for marine spatial planning in implementing the objectives and strategies of the ESSIM plan is highlighted using examples related to multiple ocean use and marine conservation and protected area planning. The article concludes by drawing out key lessons learned to date through the ESSIM process for marine spatial planning and looks to the future in terms of the development of tools and approaches for this integral aspect of integrated ocean management.     

Bioluminescent yeast estrogen assay (BLYES) as a sensitive tool to monitor surface and drinking water for estrogenicity

Estrogenic Endocrine Disrupting Chemicals (EDCs) are a concern due to their ubiquity and recognized adverse effects to humans and wildlife. Methods to assess exposure to and associated risks of their presence in aquatic environment are still under development. The aim of this work is to assess estrogenicity of raw and treated waters with different degrees of pollution. Chemical analyses of selected EDCs were performed by liquid chromatography-tandem mass spectrometry, and estrogenic activity was evaluated using in vitro bioluminescent yeast estrogen assay (BLYES). Most raw water samples (18/20) presented at least one EDC and 16 rendered positive in BLYES. When EDCs were detected, the bioassay usually provided a positive response, except when only bisphenol A was detected at low concentrations. The highest values of estrogenic activity were detected in the most polluted sites. The maximum estrogenic activity observed was 8.7 ng equiv. of E2 L(-1). We compared potencies observed in the bioassay to the relative potency of target compounds and their concentrations failed to fully explain the biological response. This indicates that bioassay is more sensitive than the chemical approach either detecting estrogenic target compounds at lower concentrations, other non-target compounds or even synergistic effects, which should be considered on further investigations. We have not detected either estrogenic activity or estrogenic compounds in drinking water. BLYES showed good sensitivity with a detection limit of 0.1 ng equiv. E2 L(-1) and it seems to be a suitable tool for water monitoring.     

An update of the Worldwide Integrated Assessment (WIA) on systemic insecticides. Part 2: impacts on organisms and ecosystems

Environmental Science and Pollution Research - New information on the lethal and sublethal effects of neonicotinoids and fipronil on organisms is presented in this review, complementing the...